1. Field of the Invention
This invention relates to improved delay detonator devices. Specifically, the present invention refers to delay detonators capable of withstanding high impact. Such delay detonators use an internal arrangement of components to rigidly lock separation distances between active components.
2. Description of the Prior Art
Delay detonators have been used in ordnance for many decades. For impact resistant warheads, the delay detonator shown in FIG. 1 represents current state of the art. This current state of the art has been known for approximately a quarter of a century. In FIG. 1, an outer casing 11 which can be made of metal, is used to hold the delay detonator components. As shown in FIG. 1, casing 11 only has a single open end. At the bottom of casing 11 detonation material is placed that provides the output function of the detonator. As shown in FIG. 1, two separate materials are used to make up the detonation material. At the very bottom of the casing, material 12 can be a standard explosive such as RDX and material 14 can be another material such as lead azide. The reason for the two different compounds is that the lead azide burns or detonates at a relatively high temperature and pressure. This detonation/burning then detonates the RDX. RDX provides the high impulse required for detonation of the next element in the explosive train.
The next component placed inside outer casing 11 is the sleeve insert 16. Sleeve insert 16 is made of metal and is slid down the inside of outer case 11 until it either contacts detonation material 14 or leaves a very slight space 18 as shown. Sleeve 16 has a limited aperture 20 whose function will be described later. Within space 22, in sleeve insert 16, the pyrotechnic delay mix 24 is inserted. Pyrotechnic delay mix 24 can be any suitable material which ignites and burns rather than detonates. Pyrotechnic delay mix 24 is usually sandwiched between holding devices 26 which can be either screen wire mesh, paper, or other suitable material. In either case, the function is to serve as a flame holder both for the entrance into and exit from pyrotechnic delay mix 24. A washer 28, which serves as an access piece to pyrotechnic delay mix 24, is then placed against one of the holding devices 26 as shown. Washer 28 may be metal, plastic, etc. Most of the volume of space 22 is left empty. This volume serves as a combustion chamber and provides the free volume that is necessary for stable combustion. The use of washer 28 at the end of the combustion chamber section limits the amount of burning/detonation materials that may be passing through space 22, as will be described further on. At the end of inner sleeve 16, a spacer 30 is placed. Spacer 30 can be made of metal, plastic, etc. As shown, spacer 30 is a cylindrical device with an aperture at one end and a matching diameter to inner sleeve 16 on the other end. Spacer 30 serves as both a holder and a throttle down device to attenuate energy into space 22.
Holding spacer 30 in proper position with inner sleeve 16 is an outer sleeve 32. Outer sleeve 32 is also made of metal or plastic. Within outer sleeve 32 and across the apertured end of spacer 30, a thin layer of paper 34 is placed. Thin paper 34 can serve as a flameholder/charge retainer in a similar fashion to holding devices 26 previously described. Holding paper 34 in place is a washer shaped device 36 which is made of plastic or any similar material. This material is filled with an igniter charge 38 placed directly against paper 34. On the opposite side of igniter charge 38 is a bridgewire mix 40. In turn, a bridgewire 56 is placed against bridgewire mix 40. Attached to bridgewire 56 are two wire leads 42 which in turn are attached to an electrical energy source 44. Holding device 36 in place is a sleeve 46 which fits within outer sleeve 32 and presses against the edges of device 36 as shown. Sleeve 46, which can be metal or plastic, is filled with glass 48. This glass-to-metal mixture serves as a stable holder that holds leads 42, sleeve 46, bridgewire 56, bridgewire mix 40, igniter charger 38, and device 36 in a fixed position. Spaces 50 and 52 have intentionally been left vacant.
Upon an electrical signal, leads 42 transmit the signal to bridgewire 56 which is heated and then ignites bridgewire mix 40. Bridgewire mix 40 in turn is detonated and then ignites the igniter charge 38 which has a controlled flame front. The flame front passes through paper 34 and spacer 30. The limitation provided by spacer 30 permits only a small fraction of the detonation particles from igniter mix 38 to pass into volume 22. The particles which reach volume 22 dissipate part of their collective energy in volume 22. The number of particles that pass into pyrotechnic delay mix 24 is decreased by washer 28. Flameholders 26 insure a uniform flame front into the pyrotechnic delay 24 and a uniform flame front out of pyrotechnic delay mix 24. The internal configuration of the components within inner sleeve 16 is to avoid misfires by either having detonation products from igniter mix 38 punch through pyrotechnic delay mix 24 and into detonation materials 12 and 14 and thus defeat the delay time desired or else the massive combustion of the detonation into volume 22 would be over so fast that pyrotechnic delay mix 24 would fail to ignite.